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BIOL 271/ BIOL271 Module 5 Exam – Microbiology
(2026/2027) | Complete Practice Questions & 100%
Accurate Answers | Portage Learning
Module goal: Explain how secretion of protein substrates to the cell surface differs from
secretion to the external environment
Module goal: Explain how bacteria transmit a signal from a stimulus from the outside to the
inside of the cell and the outcome of that signaling
TCS systems
-lots of these systems
-generally have a receptor in the membrane which send a signal to a responder in the cytoplasm
which changes conformation and goes to a promoter gene to up or down regulate
Module goal: Explain the difference between beneficial, opportunistic, and pathogenic infections
beneficial = helpful
opportunistic = if IS is down, will proliferate
pathogenic = causing disease state
Module goal: Understand how viruses use host mechanisms to establish infection
can cause cancer
Module goal: Discuss specific examples to demonstrate an understanding of the complexity of
microbial interactions with the environment
Module Goal: Discuss specific examples to demonstrate an understanding of the complexity of
microbial interactions with the human host
How do marine viruses contribute to the coral reef ecosystem?
viral mediated lysis of hosts releases dissolved organic matter (DOM) and particulate organic
matter (POM) in to the water column making them available for other microorganisms and coral
What are some extreme conditions microbes have been found in?
hydrothermal vents
The dry valleys of Antarctica (windiest, coldest, driest ecosystem known)
,What effects can microbes have on a plant and their rhizosphere?
most plant microflora found near roots.
can be commensal, pathogenic, or beneficial.
Can help attain nutrients from soil, protect from drought (forming a biofilm around roots), can
also protect from viruses.
Give 2 examples of microbiomes effecting organism behaviour.
Give 2 examples of organism behaviour effecting the micro biome.
microbiota on human skin can effect how attractive the person is to mosquitoes- could impact
disease spread
a certain bacteria abundance in mice can effect anxiety levels of the mouse
Green iguanas eat soil or feces to tailor gut microbiota to their diet.
some squid eject bioluminescent bacteria on the daily to control their symbiont populations
What is the Earth Microbiome Project and how could the data be useful.
established in order to try to determine where and what types of microbes exist on Earth.
It is estimated that less than 5% of the earth's microbiome has been cultured
this project collects the genomic sequences of many organisms from samples (viral, prokaryotic,
eukaryotic). They won't know what they're sampling but they'll have a database of genomic
sequences that could be used later to create technologies.
What are some ways biofilms negatively effect society?
biofouling on marine transport and equipment -> more fuel needed bc increased drag, corrosion,
invasive species are carried
Medical devices: biofilms can form streamers (not attached to walls) and hinder fluid flow in
devices such as catheters and stints
normal flora
Microorganisms that reside in or on the body without causing disease, introduced at birth.
aka commensal organisms
when is normal flora established?
The first 3 years of life are highly influential for your gut microbiome
flora found in babys gestational environment (placental tissue etc.). They also pick some up from
their delivery and from mum gut flora. within a couple hours mouth and nose flora are
established and within a day the gut microbiota is established.
,what factors can influence the makeup of a babies microbiome?
Delivery mode
Diet
Gestational age
Sanitation
Antibiotic treatment
are fungi more diverse on skin or in internal environments on the human body?
internal environment on mucosal surfaces
which type of organism fluctuates the most in terms of genera composition of the normal
microbiota?
fungi composition fluctuates the most
what can prolonged antibiotic treatment lead to?
fungal infections (mostly expansion of the Candida species)
can viruses be commensal organisms?
perhaps? they are found in asymptomatic people. unclear if they are helpful or harmful
The composition of commensal microbes in the human gut is directly influenced by:
a. health
b. diet
c. geographical location
d. exercise
e. all of the above
health, diet, geographical location
The composition of commensal microbes in neonates is influenced by:
a. gestational age
b. delivery method
c. food source
d. gender
e. age of mother
f. sanitation
g. antibiotic treatment
h. all of the above
gestational age, delivery methods, food source, sanitation, antibiotic treatment
In which time period is human gut flora most susceptible to changes that result in established,
individual microbiomes:
a. before birth
b. as a neotate
c. the first 3 years of life
d. up to adolescence
e. up to adulthood
, c. first 3 years of life
In humans, where is the highest diversity of commensal fungi located?
a. skin
b. mucosal surfaces
c. evenly distributed throughout body
d. humans don't have commensal fungi
b. mucosal surfaces
benefits of microbiome
-stable microenvirnments
-protection from predators and IS
-commmunication, resource sharing, HGT
-can create sub populations (division of labour) sophisticated division of labour
what signalling molecule is used for both intraspecies and interspecies communication?
Autoinducer 2 (AI2)
increased amounts of AI2 releasing from growing communities attracts others to the site
we are made up of ___ times more microbial cells than human cells as there is ____ times more
microbial genes than human genes.
we are made up of 10 times more microbial cells than human cells as there is 100 times more
microbial genes than human genes.
what are some normal flora found in the upper respiratory tract? skin? GI tract? Genital tract?
respiratory: staphylococcus and streptococcus
Skin: staphylococcus
GI: E coli., streptococcus, lactobacillus
genital tract: lactobacillus, streptocuccus
two component systems (TCS)
bacterial sensing system to detect changed in env
-uses series fo phosphorylation-dependent, post-translational, activation events
-receptors = Histidine kinase (stimulus specific membrane bound proteins)
-response regulators in cytoplasm move to chromosome to affect gene transcription
which protein receptor is used in TCS?
Histidine kinase
-stimulus specific membrane bound proteins
what are the steps of the TCS signalling pathway?
1. environmental stimuli (molecules, pH, temp)
BIOL 271/ BIOL271 Module 5 Exam – Microbiology
(2026/2027) | Complete Practice Questions & 100%
Accurate Answers | Portage Learning
Module goal: Explain how secretion of protein substrates to the cell surface differs from
secretion to the external environment
Module goal: Explain how bacteria transmit a signal from a stimulus from the outside to the
inside of the cell and the outcome of that signaling
TCS systems
-lots of these systems
-generally have a receptor in the membrane which send a signal to a responder in the cytoplasm
which changes conformation and goes to a promoter gene to up or down regulate
Module goal: Explain the difference between beneficial, opportunistic, and pathogenic infections
beneficial = helpful
opportunistic = if IS is down, will proliferate
pathogenic = causing disease state
Module goal: Understand how viruses use host mechanisms to establish infection
can cause cancer
Module goal: Discuss specific examples to demonstrate an understanding of the complexity of
microbial interactions with the environment
Module Goal: Discuss specific examples to demonstrate an understanding of the complexity of
microbial interactions with the human host
How do marine viruses contribute to the coral reef ecosystem?
viral mediated lysis of hosts releases dissolved organic matter (DOM) and particulate organic
matter (POM) in to the water column making them available for other microorganisms and coral
What are some extreme conditions microbes have been found in?
hydrothermal vents
The dry valleys of Antarctica (windiest, coldest, driest ecosystem known)
,What effects can microbes have on a plant and their rhizosphere?
most plant microflora found near roots.
can be commensal, pathogenic, or beneficial.
Can help attain nutrients from soil, protect from drought (forming a biofilm around roots), can
also protect from viruses.
Give 2 examples of microbiomes effecting organism behaviour.
Give 2 examples of organism behaviour effecting the micro biome.
microbiota on human skin can effect how attractive the person is to mosquitoes- could impact
disease spread
a certain bacteria abundance in mice can effect anxiety levels of the mouse
Green iguanas eat soil or feces to tailor gut microbiota to their diet.
some squid eject bioluminescent bacteria on the daily to control their symbiont populations
What is the Earth Microbiome Project and how could the data be useful.
established in order to try to determine where and what types of microbes exist on Earth.
It is estimated that less than 5% of the earth's microbiome has been cultured
this project collects the genomic sequences of many organisms from samples (viral, prokaryotic,
eukaryotic). They won't know what they're sampling but they'll have a database of genomic
sequences that could be used later to create technologies.
What are some ways biofilms negatively effect society?
biofouling on marine transport and equipment -> more fuel needed bc increased drag, corrosion,
invasive species are carried
Medical devices: biofilms can form streamers (not attached to walls) and hinder fluid flow in
devices such as catheters and stints
normal flora
Microorganisms that reside in or on the body without causing disease, introduced at birth.
aka commensal organisms
when is normal flora established?
The first 3 years of life are highly influential for your gut microbiome
flora found in babys gestational environment (placental tissue etc.). They also pick some up from
their delivery and from mum gut flora. within a couple hours mouth and nose flora are
established and within a day the gut microbiota is established.
,what factors can influence the makeup of a babies microbiome?
Delivery mode
Diet
Gestational age
Sanitation
Antibiotic treatment
are fungi more diverse on skin or in internal environments on the human body?
internal environment on mucosal surfaces
which type of organism fluctuates the most in terms of genera composition of the normal
microbiota?
fungi composition fluctuates the most
what can prolonged antibiotic treatment lead to?
fungal infections (mostly expansion of the Candida species)
can viruses be commensal organisms?
perhaps? they are found in asymptomatic people. unclear if they are helpful or harmful
The composition of commensal microbes in the human gut is directly influenced by:
a. health
b. diet
c. geographical location
d. exercise
e. all of the above
health, diet, geographical location
The composition of commensal microbes in neonates is influenced by:
a. gestational age
b. delivery method
c. food source
d. gender
e. age of mother
f. sanitation
g. antibiotic treatment
h. all of the above
gestational age, delivery methods, food source, sanitation, antibiotic treatment
In which time period is human gut flora most susceptible to changes that result in established,
individual microbiomes:
a. before birth
b. as a neotate
c. the first 3 years of life
d. up to adolescence
e. up to adulthood
, c. first 3 years of life
In humans, where is the highest diversity of commensal fungi located?
a. skin
b. mucosal surfaces
c. evenly distributed throughout body
d. humans don't have commensal fungi
b. mucosal surfaces
benefits of microbiome
-stable microenvirnments
-protection from predators and IS
-commmunication, resource sharing, HGT
-can create sub populations (division of labour) sophisticated division of labour
what signalling molecule is used for both intraspecies and interspecies communication?
Autoinducer 2 (AI2)
increased amounts of AI2 releasing from growing communities attracts others to the site
we are made up of ___ times more microbial cells than human cells as there is ____ times more
microbial genes than human genes.
we are made up of 10 times more microbial cells than human cells as there is 100 times more
microbial genes than human genes.
what are some normal flora found in the upper respiratory tract? skin? GI tract? Genital tract?
respiratory: staphylococcus and streptococcus
Skin: staphylococcus
GI: E coli., streptococcus, lactobacillus
genital tract: lactobacillus, streptocuccus
two component systems (TCS)
bacterial sensing system to detect changed in env
-uses series fo phosphorylation-dependent, post-translational, activation events
-receptors = Histidine kinase (stimulus specific membrane bound proteins)
-response regulators in cytoplasm move to chromosome to affect gene transcription
which protein receptor is used in TCS?
Histidine kinase
-stimulus specific membrane bound proteins
what are the steps of the TCS signalling pathway?
1. environmental stimuli (molecules, pH, temp)
